feat(js): add --includeBabelRc flag for @nrwl/js:library generator (#8793, #8600)

docs/generated/packages/js.json

@@ -59,6 +59,10 @@
             "description": "Do not update tsconfig.json for development experience.",
             "default": false
           },
+          "includeBabelRc": {
+            "type": "boolean",
+            "description": "Include a .babelrc configuration to compile TypeScript files"
+          },
           "testEnvironment": {
             "type": "string",
             "enum": ["jsdom", "node"],

e2e/js/src/js.test.ts

@@ -1,5 +1,6 @@
 import {
   checkFilesExist,
+  checkFilesDoNotExist,
   newProject,
   readFile,
   readJson,
@@ -46,6 +47,16 @@ describe('js e2e', () => {
       'match the cache'
     );
 
+    const packageJson = readJson('package.json');
+    const devPackageNames = Object.keys(packageJson.devDependencies);
+    expect(devPackageNames).toContain('@nrwl/web');
+
+    const babelRc = readJson(`libs/${lib}/.babelrc`);
+    expect(babelRc.plugins).toBeUndefined();
+    expect(babelRc.presets).toStrictEqual([
+      ['@nrwl/web/babel', { useBuiltIns: 'usage' }],
+    ]);
+
     expect(runCLI(`build ${lib}`)).toContain('Done compiling TypeScript files');
     checkFilesExist(
       `dist/libs/${lib}/README.md`,
@@ -181,6 +192,8 @@ describe('js e2e', () => {
       `dist/libs/${lib}/src/lib/${lib}.d.ts`
     );
 
+    checkFilesDoNotExist(`libs/${lib}/.babelrc`);
+
     const parentLib = uniq('parentlib');
     runCLI(`generate @nrwl/js:lib ${parentLib} --buildable --compiler=swc`);
     const parentLibPackageJson = readJson(`libs/${parentLib}/package.json`);
@@ -220,4 +233,13 @@ describe('js e2e', () => {
     expect(output).toContain('1 task(s) it depends on');
     expect(output).toContain('Successfully compiled: 2 files with swc');
   }, 120000);
+
+  it('should not create a `.babelrc` file when creating libs with js executors (--compiler=tsc)', () => {
+    const lib = uniq('lib');
+    runCLI(
+      `generate @nrwl/js:lib ${lib} --compiler=tsc --includeBabelRc=false`
+    );
+
+    checkFilesDoNotExist(`libs/${lib}/.babelrc`);
+  });
 });

packages/js/src/generators/library/library.spec.ts

@@ -13,6 +13,7 @@ describe('lib', () => {
   let tree: Tree;
   const defaultOptions: Omit<LibraryGeneratorSchema, 'name'> = {
     skipTsConfig: false,
+    includeBabelRc: false,
     unitTestRunner: 'jest',
     skipFormat: false,
     linter: 'eslint',
@@ -850,5 +851,117 @@ describe('lib', () => {
         expect(tree.exists('tools/scripts/publish.mjs')).toBeTruthy();
       });
     });
+
+    describe('--includeBabelRc', () => {
+      it('should generate a .babelrc when flag is set to true', async () => {
+        await libraryGenerator(tree, {
+          ...defaultOptions,
+          name: 'myLib',
+          includeBabelRc: true,
+        });
+
+        expect(tree.exists('libs/my-lib/.babelrc')).toBeTruthy();
+      });
+
+      it('should not generate a .babelrc when flag is set to false', async () => {
+        await libraryGenerator(tree, {
+          ...defaultOptions,
+          name: 'myLib',
+          includeBabelRc: false,
+        });
+
+        expect(tree.exists('libs/my-lib/.babelrc')).toBeFalsy();
+      });
+
+      it('should not generate a .babelrc when compiler is swc (even if flag is set to true)', async () => {
+        await libraryGenerator(tree, {
+          ...defaultOptions,
+          name: 'myLib',
+          compiler: 'swc',
+          includeBabelRc: true,
+        });
+
+        expect(tree.exists('libs/my-lib/.babelrc')).toBeFalsy();
+      });
+
+      it('should generate a .babelrc when flag is set to true (even if there is no `@nrwl/web` plugin installed)', async () => {
+        updateJson(tree, 'package.json', (json) => {
+          json.devDependencies = {};
+          return json;
+        });
+
+        await libraryGenerator(tree, {
+          ...defaultOptions,
+          name: 'myLib',
+          includeBabelRc: true,
+        });
+
+        expect(tree.exists('libs/my-lib/.babelrc')).toBeTruthy();
+
+        const babelRc = readJson(tree, 'libs/my-lib/.babelrc');
+        expect(babelRc).toMatchInlineSnapshot(`
+          Object {
+            "presets": Array [
+              Array [
+                "@nrwl/web/babel",
+                Object {
+                  "useBuiltIns": "usage",
+                },
+              ],
+            ],
+          }
+        `);
+      });
+
+      it('should generate a .babelrc when flag is not set and there is a `@nrwl/web` package installed', async () => {
+        updateJson(tree, 'package.json', (json) => {
+          json.devDependencies = {
+            '@nrwl/web': '1.1.1',
+            '@nrwl/react': '1.1.1',
+            '@nrwl/next': '1.1.1',
+          };
+          return json;
+        });
+
+        await libraryGenerator(tree, {
+          ...defaultOptions,
+          name: 'myLib',
+          includeBabelRc: undefined,
+        });
+
+        expect(tree.exists('libs/my-lib/.babelrc')).toBeTruthy();
+
+        const babelRc = readJson(tree, 'libs/my-lib/.babelrc');
+        expect(babelRc).toMatchInlineSnapshot(`
+          Object {
+            "presets": Array [
+              Array [
+                "@nrwl/web/babel",
+                Object {
+                  "useBuiltIns": "usage",
+                },
+              ],
+            ],
+          }
+        `);
+      });
+      it('should not generate a .babelrc when flag is not set and there is NOT a `@nrwl/web` package installed', async () => {
+        updateJson(tree, 'package.json', (json) => {
+          json.devDependencies = {
+            '@nrwl/angular': '1.1.1',
+            '@nrwl/next': '1.1.1',
+          };
+          return json;
+        });
+
+        await libraryGenerator(tree, {
+          ...defaultOptions,
+          name: 'myLib',
+          includeBabelRc: undefined,
+        });
+
+        expect(tree.exists('libs/my-lib/.babelrc')).toBeFalsy();
+      });
+    });
   });
 });

packages/js/src/generators/library/library.ts

@@ -12,6 +12,8 @@ import {
   toJS,
   Tree,
   updateJson,
+  readJson,
+  writeJson,
 } from '@nrwl/devkit';
 import { jestProjectGenerator } from '@nrwl/jest';
 import { findRootJestPreset } from '@nrwl/jest/src/utils/config/find-root-jest-files';
@@ -177,6 +179,40 @@ function updateTsConfig(tree: Tree, options: NormalizedSchema) {
   });
 }
 
+/**
+ * Currently `@nrwl/js:library` TypeScript files can be compiled by most NX applications scaffolded via the Plugin system. However, `@nrwl/react:app` is an exception that due to its babel configuration, won't transpile external TypeScript files from packages/libs that do not contain a .babelrc.
+ *
+ * If a user doesn't explicitly set the flag, to prevent breaking the experience (they see the application failing, and they need to manually add the babelrc themselves), we want to detect whether they have the `@nrwl/web` plugin installed, and generate it automatically for them (even when they do not explicity request it).
+ *
+ * You can find more details on why this is necessary here:
+ * https://github.com/nrwl/nx/pull/10055
+ */
+function shouldAddBabelRc(tree: Tree, options: NormalizedSchema) {
+  if (typeof options.includeBabelRc === 'undefined') {
+    const webPluginName = '@nrwl/web';
+
+    const packageJson = readJson(tree, 'package.json');
+
+    const hasNxWebPlugin = Object.keys(
+      packageJson.devDependencies as Record<string, string>
+    ).includes(webPluginName);
+
+    return hasNxWebPlugin;
+  }
+
+  return options.includeBabelRc;
+}
+
+function addBabelRc(tree: Tree, options: NormalizedSchema) {
+  const filename = '.babelrc';
+
+  const babelrc = {
+    presets: [['@nrwl/web/babel', { useBuiltIns: 'usage' }]],
+  };
+
+  writeJson(tree, join(options.projectRoot, filename), babelrc);
+}
+
 function createFiles(tree: Tree, options: NormalizedSchema, filesDir: string) {
   const { className, name, propertyName } = names(options.name);
 
@@ -196,9 +232,11 @@ function createFiles(tree: Tree, options: NormalizedSchema, filesDir: string) {
     hasUnitTestRunner: options.unitTestRunner !== 'none',
   });
 
-  if (options.buildable && options.compiler === 'swc') {
+  if (options.compiler === 'swc') {
     addSwcDependencies(tree);
     addSwcConfig(tree, options.projectRoot);
+  } else if (shouldAddBabelRc(tree, options)) {
+    addBabelRc(tree, options);
   }
 
   if (options.unitTestRunner === 'none') {

packages/js/src/generators/library/schema.json

@@ -52,6 +52,10 @@
       "description": "Do not update tsconfig.json for development experience.",
       "default": false
     },
+    "includeBabelRc": {
+      "type": "boolean",
+      "description": "Include a .babelrc configuration to compile TypeScript files"
+    },
     "testEnvironment": {
       "type": "string",
       "enum": ["jsdom", "node"],

packages/js/src/utils/schema.d.ts

@@ -15,6 +15,7 @@ export interface LibraryGeneratorSchema {
   tags?: string;
   simpleModuleName?: boolean;
   skipTsConfig?: boolean;
+  includeBabelRc?: boolean;
   unitTestRunner?: 'jest' | 'none';
   linter?: Linter;
   testEnvironment?: 'jsdom' | 'node';